A VRML-Java-Based Approach to Teaching APT Programming

Abstract

This paper describes an on-line web-based and computer-based teaching course that has been developed using Information Technology (IT), for use as a supplementary tool in teaching Automatically Programmed Tool (APT) programming. APT is one of the most widely used high-level software tools for complex numerical-controlled machining. APT programming is being offered as one of the third year elective modules in the Mechanical Engineering Department at the National University of Singapore. An APT program is a long series of commands describing the geometry of the work-piece to be machined, as well as the path that a cutter must follow in order to produce the part. HyperText Markup Language (HTML), Java and Virtual Reality Modelling Language (VRML) are the primary languages used to develop this teaching package. They are essential in presenting standard ASCII text and in adding interactivity to the teaching package. They also provide the platform for delivering two-dimensional (2–D) as well as three-dimensional (3–D) work-piece geometry and tool cutting simulations to enhance the understanding and aid in the visualization of the APT language on the Internet. The course content of this elective module has been carefully organized using a combination of linear and hierarchical structures and presented in a series of web-pages to allow students to easily grasp the concepts. Illustrations of a 3–D work-piece as well as the machining path of a cutter are often difficult on a flat 2–D and non-moving piece of transparency. The simulations of machining paths using VRML together with the interactivity offered to the students in visualizing these simulations significantly enhance the students' understanding of the concepts.